chr5-80629166-C-A

Variant names:

• chr5-80629166-C-A
• NM_000791.4:c.486-1G>T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_000791.4(DHFR):​c.486-1G>T variant causes a splice acceptor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: DHFR NM_000791.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.22

Genes affected

DHFR (HGNC:2861): (dihydrofolate reductase) Dihydrofolate reductase converts dihydrofolate into tetrahydrofolate, a methyl group shuttle required for the de novo synthesis of purines, thymidylic acid, and certain amino acids. While the functional dihydrofolate reductase gene has been mapped to chromosome 5, multiple intronless processed pseudogenes or dihydrofolate reductase-like genes have been identified on separate chromosomes. Dihydrofolate reductase deficiency has been linked to megaloblastic anemia. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2014]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 5.212766 fraction of the gene.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DHFR	NM_000791.4	c.486-1G>T		splice_acceptor_variant, intron_variant	Intron 5 of 5	ENST00000439211.7	NP_000782.1
DHFR	NM_001290354.2	c.330-1G>T		splice_acceptor_variant, intron_variant	Intron 4 of 4		NP_001277283.1
DHFR	NM_001290357.2	c.370-1G>T		splice_acceptor_variant, intron_variant	Intron 4 of 4		NP_001277286.1
DHFR	NR_110936.2	n.803-1G>T		splice_acceptor_variant, intron_variant	Intron 3 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DHFR	ENST00000439211.7	c.486-1G>T		splice_acceptor_variant, intron_variant	Intron 5 of 5	1	NM_000791.4	ENSP00000396308.2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 23

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jan 13, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 5 of the DHFR gene. It does not directly change the encoded amino acid sequence of the DHFR protein. It affects a nucleotide within the consensus splice site. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with DHFR-related conditions. ClinVar contains an entry for this variant (Variation ID: 1501340). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Uncertain	0.95	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.55		Position offset: -9
DS_AL_spliceai		0.96		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr5-79924985;